High durability touch screen and method for manufacturing

ABSTRACT

A method for manufacturing a touch screen that deposits a conductive layer or coating directly onto a surface of a sheet or ribbon or roll of thin glass material. The coated thin glass material may be cut to the desired shape or substrate for use as the outer, thin glass substrate of the touch screen device. Spacer elements and/or other functional coatings or layers or the like may also be applied to the conductive layer or opposite surface of the thin glass ribbon. Optionally, a functional coating or layer may be deposited or applied to a surface of a pre-cut thin glass substrate. The coated pre-cut thin glass substrate may be used as a top sheet for lamination as the protective top sheet of a touch screen device.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims benefit of U.S. provisional application,Ser. No. 60/484,713, filed Jul. 3, 2003 (Attorney Docket DON03 P-1105),which is hereby incorporated herein by reference in its entirety.

FIELD OF INVENTION

The present invention relates generally to touch screens and methods formanufacturing touch screens.

BACKGROUND OF INVENTION

As the use of touch screens, such as for public information kiosks,portable devices, and gaming applications and the like, increases, sodoes the need for more durable touch screen designs. Use of laminationconfigurations is a known technique to enhance durability of and addfeatures (such as conductive, anti-glare, and anti-reflective coatings)to the touch screens. For example, using a transparent, conductivelycoated flexible plastic material, such as transparent conductivelycoated PET laminated to ultrathin glass (having a glass thicknesspreferably less than about 0.3 mm in thickness, more preferably lessthan about 0.2 mm in thickness, most preferably less than about 0.1 mmthickness) as the top sheet in a conventional resistive touch screendesign (as shown in FIG. 1) is known in the art of touch screenmanufacturing. The coating of flexible PET with a transparent conductivecoating, such as by a web coating process, is also common processknowledge.

A conventional resistive touch screen device is shown in FIG. 1. In thisdevice, a resistive touch screen 60 uses a transparent rigid substrate10, which can be glass or plastic. A transparent conductive thin film 20(such as indium tin oxide in the sheet resistance range of about 150 toabout 900 ohms per square, sometimes in the range of about 400 to about600 ohms per square with a physical thickness of about 500 angstroms orless) may be deposited onto a surface 24 of substrate 10. Insulatingspacer dots 30 (as known in the interactive information display art),may be arranged on surface 22 of transparent conductive film 20, inorder to provide separation between surface 22 and a second transparentconductive film 51 (that is deposited on a flexible substrate 50) so asto avoid false-touch sensing of the touch screen. The transparentconductive film 51 is typically indium tin oxide, and may be depositedusing a conventional coating deposition technique know as physical vapordeposition (preferably by web coating) on flexible transparent substrate50, typically PET. This flexible transparent substrate may be laminatedor attached using conventional adhesive materials to the ultrathin glasssubstrate 40.

Although the above configuration can work well in certain circumstances,steps involved in laminating the PET substrate to the ultrathin glasssubstrate can be challenging and costly. Thus, there is a need for amore economical way of furnishing a transparent conductive coated,ultrathin glass top sheet for a display device, in particular, aresistive touch device.

SUMMARY OF INVENTION

The present invention provides a method to achieve a durable touchscreen without the need for lamination of the PET film or substrate tothe ultrathin glass substrate for the top sheet of, for example, aresistive touch screen product configuration.

According to an aspect of the present invention, a method ofmanufacturing a high durability touch screen comprises deposition of atransparent conductive thin film directly on an ultrathin glasssubstrate, preferably using vacuum based physical vapor deposition suchas sputtering. The ultrathin glass substrate may be coated with one ormore transparent conductive or semi-conductive films, and may be used,for example, as the top sheet in a display or touch screen device.Furthermore, the method of the present invention may render economicallythe addition of other functional coatings associated with top sheets fordisplay devices, such as anti-glare coatings or diffuser surfacecoatings and/or anti-reflective coatings, and/or anti-abrasion coatingsor the like. Aspects of the present invention may be equally suitablefor use in manufacturing resistive touch screen devices and capacitivetouch screen devices.

According to another aspect of the present invention, a method ofmanufacturing a touch screen includes providing a first substrate havinga substantially transparent conductive coating on a surface thereof andproviding a sheet of glass having a thickness of less than or equal toapproximately 0.3 mm. A substantially transparent conductive film isdeposited on a surface of glass sheet. At least one functional coatingis deposited at at least one surface of the glass sheet. The functionalcoating comprises at least one of an anti-glare coating, a diffusersurface coating, an anti-reflective coating and an anti-abrasioncoating. At least one glass substrate is cut from the coated glass sheetand the glass substrate is assembled to the first substrate to form atouch screen device.

The glass sheet may comprise an elongated glass ribbon, and the methodmay include unrolling the glass ribbon from a feed roll having the glassribbon wound at least partially therearound. The glass ribbon may berolled or wound onto a take-up reel after the at least one functionalcoating is deposited on the surface.

The at least one functional coating may be deposited at a surface of theglass sheet that is opposed to the surface on which the substantiallytransparent conductive coating is deposited. The surface of the glasssheet may be washed before the at least one functional coating isdeposited thereon.

According to another aspect of the present invention, a method ofmanufacturing a capacitive touch screen includes providing a firstsubstrate having a substantially transparent conductive coating on asurface thereof and providing a glass substrate having a thickness ofless than or equal to approximately 0.3 mm. At least one functionalcoating is deposited at a surface of the glass substrate. The functionalcoating comprises at least one of an anti-glare coating, a diffusersurface coating, an anti-reflective coating and an anti-abrasioncoating. The glass substrate is assembled to the first substrate to forma capacitive touch screen device.

The present invention encompasses reel to reel application deposition ofa transparent conductive coating (such as indium tin oxide, or doped tinoxide or the like), preferably in a vacuum environment, and achievementof further processing, such as heating, to fully form transparentconductive thin films, preferably while the ribbon of ultrathin glasstraverses from the feed reel to the take-up reel in a reel to reelprocess. Optionally, whether in the same vacuum deposition step orbefore, or after, anti-reflection coatings can be deposited if desired(such as described in U.S. patent application Ser. No. 09/883,654, filedJun. 18, 2001 by Getz for ENHANCED LIGHT TRANSMISSION CONDUCTIVE COATEDTRANSPARENT SUBSTRATE AND METHOD FOR MAKING SAME (Attorney Docket DON03P-907), which is hereby incorporated herein by reference). Further,either before or after either or both of the above operations, one ormore anti-glare coatings (AGC) or diffuser surface coatings can bedeposited such as by wet chemical deposition (such as disclosed in U.S.Pat. Nos. 5,725,957; 6,001,486; 6,087,012; and 6,440,491, which arehereby incorporated herein by reference). Furthermore, the functionalityof the flexible ultrathin glass substrate may be further enhanced bysilk screening spacer elements, which are typically referred to in theresistive touch screen art as “spacer dots” (such as described in U.S.Pat. No. 6,627,918 for SPACER ELEMENTS FOR INTERACTIVE INFORMATIONDEVICES AND METHOD FOR MAKING SAME (Attorney Docket DON03 P-917), whichis hereby incorporated herein by reference), onto the ultrathin glasssubstrate.

Thus, as indicated above, functional coatings, such as transparentconductive coatings, anti-glare coatings or diffuser surface coatings,anti-reflective coatings and/or anti-abrasion coatings, can be applieddirectly to the ultrathin glass (having a glass thickness preferablyless than about 0.3 mm in thickness, more preferably less than about 0.2mm thickness, and most preferably less than about 0.1 mm thickness),preferably while a ribbon of this ultrathin glass is traversing from afeed reel to a take up reel in a reel to reel process. Alternatively,such functional coatings can be directly applied to a pre-cut sheet orpre-cut shape of ultrathin glass without the need to use a reel or areel to reel process.

These and other objects, advantages, purposes and features of thepresent invention will become apparent upon review of the followingspecification in conjunction with the drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a sectional view of a conventional resistive touch screen;

FIG. 2 is a sectional view of a resistive touch screen in accordancewith the present invention;

FIG. 3 is a schematic of a process for manufacturing the touch screen ofFIG. 2 in accordance with the present invention;

FIG. 4 is a sectional view of a capacitive touch screen in accordancewith the present invention; and

FIG. 5 is a schematic of a process for manufacturing the touch screen ofFIG. 4 in accordance with the present invention.

DETAILED DESCRIPTION

Referring now to the drawings and the illustrative embodiments depictedtherein, a resistive touch screen 160 in accordance with the presentinvention is shown in FIG. 2. Resistive touch screen 160 includes atransparent rigid substrate 110, which can be glass, polymeric, acrylic,plastic or the like, most preferred a transparent plastic cyclic olefincopolymer (such as described in U.S. patent application Ser. No.09/946,228, filed Sep. 5, 2001 by Ippel et al. for IMPROVED PLASTICSUBSTRATE FOR INFORMATION DEVICES AND METHOD FOR MAKING SAME (AttorneyDocket DON03 P-910), which is hereby incorporated herein by reference),with a transparent conductive or semi-conductive thin film 120 (such asindium tin oxide (ITO) or the like in the sheet resistance range ofabout 150 to about 900 ohms per square, most preferably in the range ofabout 400 to about 600 ohms per square, with a physical thickness ofabout 500 angstroms or less) deposited thereon, such as by sputteringonto a surface 124 of substrate 110. Touch screen 160 also includes anultrathin glass substrate 140 having a transparent conductive orsemi-conductive thin film 150 (such as indium tin oxide (ITO) or thelike in the sheet resistance range of about 150 to about 900 ohms persquare, most preferably in the range of about 400 to about 600 ohms persquare, with a physical thickness of about 500 angstroms or less)deposited on a surface 126 of substrate 140. The substrate 140 is spacedfrom substrate 110 and includes a plurality of spacer elements or spacerdots 130 silk-screened or otherwise applied to a surface 122 of theconductive thin film 150, as described below. A user may then touch theouter surface 128 of substrate 140, which may press substrate 140 andconductive thin film 150 toward and into contact with conductive layer120 of rigid substrate 110 to use the touch screen 160.

A preferred method to fabricate the touch screen construction of FIG. 2is shown in FIG. 3. An elongated, transparent, flexible, ultrathin glasssubstrate sheet or roll or ribbon 212 (which may be cut to form theultrathin glass substrate 140 of touch screen 160) is processed in areel to reel process as follows. The flexible ultrathin glass substratesheet 212 is transferred, such as via any known web handling method,from a feed reel 270 into a washing system 210, such as a plasmacleaning process, electrostatic cleaning process, or ultrasonic cleaningprocess or the like. The washing cycle or step is followed by thin filmdeposition in a physical vapor deposition vacuum chamber 220. Thetransparent conductive thin film 150 (such as indium tin oxide (ITO) inthe sheet resistance range of about 50 to about 500 ohms per square,most preferably in the range of approximately 150 to 350 ohms persquare, and with a physical thickness about 500 angstroms or less) isdeposited via a physical vapor deposition technique (such as sputteringor the like) on a surface 214 of the ultrathin glass ribbon 212.Optionally, an anti-reflective thin film can also be deposited at thispoint on one or both surfaces 214 and 216 of the ribbon 212 prior to thedeposition of the conductive film.

The flexible ultrathin glass substrate ribbon 212 may then enter a spraydeposition chamber 230, and an anti-glare coating or diffuser surfacecoating (such as disclosed in U.S. Pat. Nos. 5,725,957; 6,001,486;6,087,012; and 6,440,491, which are hereby incorporated herein byreference) may be deposited on surface 216 of the ultrathin glass sheetor ribbon 212 via chemical spray deposition. Anti-reflective coatingscan also be deposited at this point via wet chemical deposition (such asby utilizing the principles described in U.S. patent application Ser.No. 09/883,654, filed Jun. 18, 2001 by Getz for ENHANCED LIGHTTRANSMISSION CONDUCTIVE COATED TRANSPARENT SUBSTRATE AND METHOD FORMAKING SAME (Attorney Docket DON03 P-907), which is hereby incorporatedherein by reference) or by other known techniques, without affecting thescope of the present invention.

The flexible ultrathin glass substrate then enters a curing chamber 240to cure (such as by heating, preferably by using an infrared heater, orultraviolet heater, or convection heater or the like) the conductivethin film, the anti-glare coating and/or the anti-reflective coating.The flexible ultrathin glass substrate ribbon 212 then has spacer dots130 silk-screened on surface 214 in a silk screen chamber 250. This isfollowed by a UV or low temperature thermal curing stage 260 to solidifythe spacer dots (such as described in U.S. Pat. No. 6,627,918 for SPACERELEMENTS FOR INTERACTIVE INFORMATION DEVICES AND METHOD FOR MAKING SAME(Attorney Docket DON03 P-917), which is hereby incorporated herein byreference) followed by the winding of the flexible ultrathin glassribbon 212 onto the take up reel 280. The finished flexible ultrathinglass sheet or ribbon 212 is then post cut using any known orconventional glass cutting methods, such as laser scribing or mechanicalscoring or the like, into the desired top sheet size, ready forlamination as the top sheet of the resistive touch screen. The device isthen inspected and tested electronically. The resulting product is thecomplete interactive information device.

Optionally, the anti-glare coating (AGC) or diffuser surface coating maybe applied to or deposited on one surface/side of the ultrathin glass,and the transparent conductive layer (which may comprise a transparentconductive PET layer) may be laminated to the opposing surface/side ofthe anti-glare coated ultrathin glass to form the ultrathin top sheet ofthe touch screen device. The coatings and layers may be applied orlaminated to ultrathin glass in the ribbon or roll or reel-to-reel form(as discussed above) or may be applied or laminated to ultrathin glassin a sheet or lite form, or may be applied or laminated to ultrathinglass substrates (after the substrates are cut from a sheet or lite orribbon or roll), without affecting the scope of the present invention.

Referring now to FIGS. 4 and 5, aspects of the present invention arealso useful for capacitive touch screen technology. Such capacitivetouch screens may similarly benefit from the utilization of the flexibleultrathin glass with anti-glare coatings or diffuser surface coatings,anti-reflective coatings and/or anti-abrasion coatings fabricated asdescribed above. Ultrathin glass can be laminated directly to thecapacitive touch screen product configuration providing a preferreddurable capacitive touch screen.

An example of the present invention as described for a capacitiveinteractive touch device is shown in FIG. 4. In this device, acapacitive touch screen 360 uses a transparent rigid substrate 310,which can be glass, polymeric, acrylic, plastic or the like, mostpreferred a transparent plastic cyclic olefin copolymer (such asdescribed in U.S. patent application Ser. No. 09/946,228, filed Sep. 5,2001 by Ippel et al. for IMPROVED PLASTIC SUBSTRATE FOR INFORMATIONDEVICES AND METHOD FOR MAKING SAME (Attorney Docket DON03 P-910), whichis hereby incorporated herein by reference) with a transparentconductive thin film 320 (such as indium tin oxide or antimony doped tinoxide in the sheet resistance range of about 1000 to 3,500 ohms persquare, most preferably in the range of about 1,500 to 2,500 ohms persquare, with a physical thickness of about 600 angstroms or less)deposited onto a surface 324 of substrate 310. The capacitive touchscreen 360 includes an ultrathin glass substrate 340, which may have ananti-glare coating or diffuser surface coating applied to or depositedon an outer surface 328 of the substrate, as discussed below.

A preferred method to fabricate the capacitive touch screen constructionof FIG. 4 is shown in FIG. 5. The flexible ultrathin glass substrate 340may be pre-cut, such as from provided sheets or lites or the like, tothe desired dimensions using any known or conventional glass cuttingtechniques, such as laser scribing or mechanical scoring or the like.The pre-cut substrate 340 can then mounted onto the vacuum fixture 405for transfer to a washing chamber or device or system 410 for washingthe substrate, such as by using known or conventional washingtechniques, such as plasma cleaning, electrostatic cleaning, orultrasonic cleaning processes or the like. The ultrathin glass substratemounted on the vacuum fixture then enters the wet chemical spray chamber430 for the anti-glare coating process (such as disclosed in U.S. Pat.Nos. 5,725,957; 6,001,486; 6,087,012; and 6,440,491, which is herebyincorporated herein by reference), which deposits the anti glare coatingor diffuser surface coating 350 onto the surface 328 of the ultrathinglass substrate 340. The substrate and anti-glare coating aretransferred to the post curing chamber 440 to cure (such as by heating,preferably by using an infrared heater, or ultraviolet heater, orconvection heater or the like), while affixed to the vacuum fixture. Thefinished flexible ultrathin glass top sheet is then ready for laminationas the protective top sheet of a capacitive touch screen. The device isthen inspected and tested electronically. The resulting product is thecomplete interactive information device.

The present invention thus provides a method for manufacturing aresistive touch screen which deposits the conductive layer or coatingdirectly onto a surface of a sheet or ribbon or roll of ultrathin glassmaterial, which may then be cut to the desired shape for use as theouter, ultrathin glass substrate of the touch screen. The spacerelements and/or other coatings or layers or the like may also be appliedto the conductive layer of the ultrathin glass ribbon. The presentinvention thus provides a low cost method for manufacturing a highlydurable touch screen device. The present invention also provides acapacitive touch screen and method for manufacturing the capacitivetouch screen.

Changes and modifications in the specifically described embodiments maybe carried out without departing from the principles of the presentinvention, which is intended to be limited only by the scope of theappended claims as interpreted according to the principles of patentlaw.

1. A method of manufacturing a touch screen, said method comprising:providing a first substrate having a substantially transparentconductive coating on a surface thereof; providing a sheet of glass,said glass sheet having a thickness of less than or equal toapproximately 0.3 mm; depositing a substantially transparent conductivefilm on a surface of said glass sheet; depositing at least onefunctional coating at at least one surface of said glass sheet, said atleast one functional coating comprising at least one of an anti-glarecoating, a diffuser surface coating, an anti-reflective coating and ananti-abrasion coating; cutting at least one glass substrate from saidcoated glass sheet; and assembling said glass substrate to said firstsubstrate to form a touch screen device.
 2. The method of claim 1,wherein said glass sheet comprises an elongated glass ribbon.
 3. Themethod of claim 2 including unrolling said glass ribbon from a feed rollhaving said glass ribbon wound at least partially therearound.
 4. Themethod of claim 3 including rolling said glass ribbon onto a take-upreel after said at least one functional coating is deposited on saidsurface.
 5. The method of claim 1 including disposing spacers on saidsurface of said glass sheet.
 6. The method of claim 5, wherein saidsubstantially transparent conductive coating, said spacers and said atleast one functional coating are disposed at at least one surface ofsaid glass sheet as said glass sheet traverses from a feed reel to atake-up reel.
 7. The method of claim 1, wherein said at least onefunctional coating is deposited at a surface of said glass sheet that isopposed to the surface on which said substantially transparentconductive coating is deposited.
 8. The method of claim 1 includinglaminating said glass sheet to a second substrate.
 9. The method ofclaim 1 including depositing an anti-glare coating at a surface of saidglass sheet.
 10. The method of claim 1 including depositing a diffusersurface coating at a surface of said glass sheet.
 11. The method ofclaim 1 including depositing an anti-reflective coating at a surface ofsaid glass sheet.
 12. The method of claim 1 including depositing ananti-abrasion coating at a surface of said glass sheet.
 13. The methodof claim 1 including washing at least one surface of said glass sheetbefore said at least one functional coating is deposited thereon.
 14. Amethod of manufacturing a capacitive touch screen comprising: providinga first substrate having a substantially transparent conductive coatingon a surface thereof; providing a glass substrate, said glass substratehaving a thickness of less than or equal to approximately 0.3 mm;depositing at least one functional coating at a surface of said glasssubstrate, said at least one functional coating comprising at least oneof an anti-glare coating, a diffuser surface coating, an anti-reflectivecoating and an anti-abrasion coating; and assembling said glasssubstrate to said first substrate to form a capacitive touch screendevice.
 15. The method of claim 14 including disposing spacers on saidsurface of said glass substrate.
 16. The method of claim 14 includinglaminating said glass substrate to a second substrate.
 17. The method ofclaim 14, wherein said at least one functional coating comprises ananti-glare coating.
 18. The method of claim 14, wherein said at leastone functional coating comprises a diffuser surface coating.
 19. Themethod of claim 14, wherein said at least one functional coatingcomprises an anti-reflective coating.
 20. The method of claim 14,wherein said at least one functional coating comprises an anti-abrasioncoating.
 21. The method of claim 14 including washing at least onesurface of said glass substrate before said at least one functionalcoating is deposited thereon.
 22. A method of manufacturing a touchscreen, said method comprising: providing a first substrate having asubstantially transparent conductive coating on a surface thereof;providing a sheet of glass, said glass sheet having a thickness of lessthan or equal to approximately 0.3 mm, said glass sheet having a firstsurface and a second surface opposed to said first surface; depositing asubstantially transparent conductive film on said first surface of saidglass sheet; depositing at least one functional coating at said secondsurface of said glass sheet, said at least one functional coatingcomprising at least one of an anti-glare coating, a diffuser surfacecoating, an anti-reflective coating and an anti-abrasion coating; andassembling said glass sheet to said first substrate to form a touchscreen device.
 23. The method of claim 22, wherein said glass sheetcomprises an elongated glass ribbon, said method including cutting atleast one glass substrate from said glass sheet.
 24. The method of claim23 including unrolling said glass ribbon from a feed roll having saidglass ribbon wound at least partially therearound.
 25. The method ofclaim 24 including rolling said glass ribbon onto a take-up reel aftersaid conductive coating is deposited on said first surface and said atleast one functional coating is deposited on said second surface. 26.The method of claim 22 including disposing spacers on said first surfaceof said glass sheet.
 27. The method of claim 22, wherein said glasssheet comprises a cut substrate.
 28. The method of claim 27 includinglaminating said cut substrate to a second substrate.
 29. The method ofclaim 22, wherein depositing at least one functional coating comprisesdepositing an anti-glare coating at said second surface of said glasssheet.
 30. The method of claim 22, wherein depositing at least onefunctional coating comprises depositing a diffuser surface coating atsaid second surface of said glass sheet.
 31. The method of claim 22,wherein depositing at least one functional coating comprises depositingan anti-reflective coating at said second surface of said glass sheet.32. The method of claim 22, wherein depositing at least one functionalcoating comprises depositing an anti-abrasion coating at said secondsurface of said glass sheet.
 33. The method of claim 22 includingwashing said first surface of said glass sheet before said conductivecoating is deposited thereon.
 34. The method of claim 22 includingwashing said second surface of said glass sheet before said at least onefunctional coating is deposited thereon.